Process for treating hygroscopic materials



Dec. 29 1925.

A. C. BUENSOD PROCESS FOR TREATING HYGROSCOPIC MATERIALS Filed lDe@l 30, 1921 2 sheets-sheet 1 De@ ,29' A1925.2

' A. C. BUENSOD v vE RCFJSS-FOR TREATING HVYGROSCOIIG MATERIALS 2 Sheets-sheet 2 Filed Dec. 3410;, 192.1

Patented nec, 29,; 192s.

" UNITED STATES -PA'TEN'T 'o`FFflCE.'-Y

Amman examina' nUENson, 'or New' Yoan-N. Y., assIeNon. 'ro cnam unaniem ING conronn'rrom or NEW Yoan, N.- Y., A coaro'nA'rIoN or New roux.

' 'rnocnss Foia-T'nEATINe renoscorr surname:

limitation mea December 3o, 1921, serial No. 525,991.

To all wlw/omit may amera.' Be it known that I, Airman CHARLES BUn'Nsoo, 'a'citizen of the United States of America, vand a resident of the city, county, andState of New Yoi'lghave invented cer-1.

"f'tainnew and vuseful?Improvements in Proce'ss for treating` hygroscopic materials, and

esses for Treating Hygroscopie Materials,

of which the 'following is 'a ull', clear, and

exact-description; My invention relatesI generallyto a procmore particularly to such a processin which totheot er. Y I The principal object of my inventlon has' irrespective of the' amount of moisture'eon-4 Ythev materials are-passed, preferably .in Qa drier of the tunnel type, continuously or periodcall l.through the drier from one end been toprovide a proccss'bywhich' a hygroi scopic product (such as tobacco or silk) may -v have 'a regulated and definite' moisture content orregain, at theexit end of the drler tent of the material introduced into the drier `.and also irrespective, ofthe speed at which the product is dried.

Inv general, my process comprises the pas- Lsa'ge oftlematerial through a chamber or compartmetwhich'is provided 'withheating means preferably controlled automatically. In thistchamber the material isf-mains' .tained at the proper. temperature l"as it is V continuously passing therethroutglht The v-niatei'ial is then passed into and mayY bespraysV `of 'water or jets o vsteam located in the chamber, or moist 'air supplied l'to'.the chamber; from s1 1itable` moistenin'g means or rmois't ain-taken -from the first chamber. -The controlof tem erature and' moisture content is also pre erablyv vautomatic; From thelsecond'chamber, the material -is *passed -on vinto and'througha jth-ird chamber, where. it is subjected'to'A relatively moist air, havinga temperature pre'- -fperature and relative humidity thereof changed preferably by means of heaters. An

automatic control for-the temperature and moisture content/is providedforfthis chamber. vAll-the automatic means are adjusted rough a] second' chamber or lcompartment which is also rovided with-'heatlng means, and inaddition to'these meians, moistening meansare'also-provided. 1 These moistenin means I so that the finished product, as it emerges process as capable of being carried outl by the use of three chambers or three pro essive stages, still it' will be obvious-to t ose skilled in the art that myinvention canbe practiced lby employing Vonly two chambers that many other forms of driers and arequal eiiiciency. In the drawings: Fig.' 1 shows a longitudinal sectional rangements of .parts might' be used with' While. I have shown and'described'my l view 'of .the drier,.taken' on Vline 1 ;-1 of`- Fi 2.' Y

gig. 2`is` a plan view thereof.

Fig. 3 is a .sectional-view takenon line tion -view vv showing one ofthe laps'58. j

suitable conveying 'mounted upon 'suitable pulleys', and idlers,

through one 'of the partitions', I;

The drier is'of."the tunnelftype, vhaving means '10; which are as shown 1n the' drawings, and provided with some suitable means for moving them. l1 is the end wall of the drier, at'the entrance end thereof. '12 is a artition arranged withf' in the drier; andP orming, with the Vend wall 11, afhamber 13. 'Amother partition 1d is provided, which, with the partition 12, forms a'chamber 15. 16is the .end wall of the' chamber at the 'exit end thereof, andA forms, 'with the partition-.14, a chamber 17j 'Arranged along thev top of these chambers and inolosed within the same',y are aplurali of fans 18, hich are rovided with suitab e means for riving t esame (not shown), whereby vthet conditioned air within the chambers is causedto be circulated through and between lthe material suspended and passing' through the chambers. f

' Arran ed'at one side ,of chamber.13, and prefrab y midway of -its lengt isano: set "compartment 19, whereby an" may be taken 'from chamber', 13 at all "elevatiom' -.,the'reof. A pipe 20, having a damper 21, is

connected atl one end to the onset compartlll ment 19 of chamberl3 and at its other end to the chamber 15, whereby the damp air from chamber 13 may be conducted to chamber 15. A branch opening 28 is `provided in the pipe 20 through which some of the moist air may be removed from the chamber 13. Y

The chamber 13 is provided with heating means, preferably inffthe form of steam heating coils 22 and 23. rllhese coils are preferably divided midway the length of this chamber, and they may be controllcd automatically by means of a thermostat 25. This thermostat is arranged preferably near the exit end of this chamber, so thatthe temperature of the air after it has passed between and in contact with the material will actua'te the thermostat, (which has been set at a predetermined temperature),

and it in turn will regulate the heating effect of the coils. Diaphragm valves 26 and 27 are provided, and are connected with the thermostat 25, and this valve controls the supply of steam to the steam coils 22 and 23. respectively.

The chamber 15 is provided with both heating means and moistening means. The heater 30, which is preferably of the pipe coil type, issupplied with steam, the flow of which is controlled by the valve 33. rlhe moistening means comprises preferably wa pipe 32, which is perforated at intervals, and through which fluid, controlled by the valve 31. is supplied. This Amoistening Huid may be in the formpf water or steam. A regulator 34 having a wet bulb 35 and a dry bulb 36 is provided for ycontrolling the conditions within the chamber 15. The valve 31 is connected to the wet bulb 35 and a valve 33 is connected to the dry bulb 36. The regulator 34 -is a standard instrument and is ofthe type in which samples of air being tested are drawn first over the dry bulb and then over the wet bulb. 1n order to accomplish the sampling of the air in this chamber, a pipe 37 extends down through the center of the chamber and has its inlet end arranged preferably below the product being dried. The upper end of this pipe is connected so that the air is drawn over the taken from chamber 13 is passed through the pipe 20 and discharged into the chamber 15, whereby it is not necessary to supply a great deal of moisture through the pipe 32. A damper 39 is'also provided in the partition 12, so that the moisture laden air 'y from chamber 13 may alsol pass linto chamber 15.

The chamber 1,7 is the last chamber through which the material passes before it meneer is discharged from they appaiatus, and this chamber is provided with neither heating nor moistening means. It is, however, provided with an inlet pipe and an| outlet pipe 46. The inlet pipe and outlet pipe are connected with any suitable apparatus for producing relatively cool, moist air, or air having a low dew point. The temperature of the air is preferably controlled by means of a heater 47, which is arranged between the pipe 48 coming4 from the moisgtening apparatus and pipe 45 leading tothe chamber 17. This heater is.. provided with any suitable heating means 49, and with a partition 50, whereby air may either pass through the heating means 49 or directly to thepipe 45. Dampers 51 and 52 are provided, whereby all ot' the air or portions thereof may be by-passed through the heating means 49.-

An air motor 53 is provided, which controls the positions of the dampcrs 51 and 52.

The chamber 17 is provided with a hygro-l stat 54 which is arranged near the exitfend thereof, and which is vactuated by thepmoisf ture content of the air after it leaves the products being treated. rlhe hygrostat by being connected to the air motor 53 controls the amount of heated air supplied to lthe chamber 17, and, therefore, the temperature of the air within the chamber. This hygrostat is preferably arranged beneath the discharge pipe 46, so that it is controlled-by the conditions of the product beingvtreated as it leaves the chamber 17. A partition 55 is provided in chamber 17, preferably midway its length., This partition does not ex.- tend to the extreme top of the chamber, but

serves to divide the chamber into two sepa-l rate compartments which will be separately treated by the 'sameain It will'be understood that the openings in the partitions of the apparatus through which the conveyors andthe product pass may be provided with any suitable means for effectively closing the openings, such as canvas flaps 58 or the like (sec Fig. 4). A plurality of hand holes 62 are preferably provided throughout the length of the apparatus, whereby the material being dried may be sampled.

As shown in Fig. 3, l employ four conveyors, suitably arranged within the drier. At the side of these` conveyors is a space 58 in which the heating vmeans and moistening means are preferably arranged. The fans are arranged at one side and above this space, and serve' to draw the air surrounding the conveyors and preferably force it downwardly through 'the heating or moist-v ening means, and :thereby cause it to be circulated between `and in contact with the surfaces of the material supportedby the conveyors. n A

In carrying out my process, the material is supported from suitable frames by the conveyors or placed ldirectly upon the eX- posedlendrof the conveyors atithe entrance `end of the drier and is fed eithercontinuously or periodically-into the same. As the vmaterial enters the chambery13, it is subi 'ected to heat which-is supplied preferably y means of the heaters 22 and 23, there being nofattemnt toward. moisture control in this chamber.

As hereinbefore pointed out,.the thermostat 25Pis arranged near the end 'of the chamber and in a position where it will be subjected to vthe air that has f vpassed 4between and has come in contact y'controlled by the .damper-'39,. Since they `material is subjected to moisture as l'well with the material which is just leaving'the chamber.v

as heat, the dry bulb 36 and wet bulb 35 are utilized to. controlthe conditions within this 1 chamber. The regulator 34 is arranged near the exit end of the chamber A15, where it will be subjected to a1r conditions which represent veryclosely the conl dition of the tobacco as it` leaves the cham ber. This is brought about'because the airby .passing continuously through the chamberend coming in contact with the material brings thel material up to the predetermined condition. l.In chamber 15, 'I

.j have found it'is preferable to maintain a 40.'

" so regulated that it will lea-vethis cham' ber and enter chamber 1 7 having a moisture tent of ten per cent whenthe ing treated ff leaves the drier, it1 s desirable xed wet bulb depression such as would normall reduce' the moisture content to a point h. would be below the' moisture conif it were desiredto have afmoisture conproduct beto` have the conditions withinchamber 15 contentof seven or eight per cent."` lThus, {'.it' will be-necessar to supply only two or .three `per cent'ad itional moistl'irel content to the material in the last chamber or chamber .17.

A large amount'of the moisture carried i by the air in..the Vchamber 15 .is supplied .b t ve chamber; and, in case the' relative hu-` midityofthe air in the chamber is too great, the' moist'eningmeans would be shut' the .material which is being treated in o i v'and vthej'frelative humidity reduced by the normal leakage of the air ,from the chamber.

. the chamber'17, it is necessa 4materials to a temperature su stantially the chamber 15, it

passes through partition 14 and enters'A chamber 17. As the materials pass into to cool such same as .that prevailing in chamber 17 These chambers are referably separated as completely as possib e, and in chamber 17 l the.`material is subjected to relatively cool air,- which has been (previously saturated and its temperature an relative humidity controlled by suitable. heating means, such as; the heater 47. The chamber 17 is subjectedl to cool, saturated air which has a dew point lower than the dew oint of the airl in the chamber 15, but havlng a relative humidity which is higher than that of chamber 15. Since the saturated air which is blown int/o the chamber 17, after recirculating through `the chamber one or moretimes will assume `a condltion closely corresponding to that of the material, the hygrostat 54 is placed at the exit end of the chamber, so that the conditionswithin the chamber will be governed the condition of the product being treatas it leaves the chamber. The control in the chamber 17 preferably operates to raise the temperature of the airbefore or as it enters the chamber while maintaining 1t' at a constant dew point. Ifthe tempera` ture of the air is raised, the relative humidity lowered, and it will not tend to add molstureto the material, while if no heat is added to the air it will add moisture to the material as required. This forms a very eiiicient means of regulatin the moisture or dryu'llelfectof the air in t e final chamber 17. e temierature in chamber 17 is much lower than t it is preferably only slightl above the temperature of the room, so t at the material when it comes out .of the drier will have practically the same temperature as that f the room, and, therefore, will not loseits moisture by evaporation when cooling. It is well known that when` material is absorblng moisture it gives ofi' a corresponding amount of heat, so that the material itself .serves to heat the air and lower its relative' humidity by temperature, 4as well as by absorption. For this' reason, a volume regulation could be used advantageousl to con# trol the tem erature and relative umidity within the ,c amber 17 instead o f the heating means shown and' described. The heater control, however, '1s vpreferable since it provides more accurate regulation and per- .mite of drying the materia as well as moistening 1t. The-'volume regulation does not permit dryin the material but is almostentirely'limite to moisfening it.- Such a volu lme regulation may be accomplished by providing a damper 60 which is controlled y an air motor 61, operated by the hygrstat 54, forre lating the amount of conditioned a owed to pass into the chamat of chambers 13 and 15, andI ber. It is obvious that such a volume regu lation is not suitable for drying the material for the reason that there would be no source of heat to lower the relative humidity. As hereinbefore stated, it is preferable to maintain a moisture'content in the material leaving the chamber l5 which is two or three per cent lower than that which `is required in the finished product. This has the effect of maintaining active drying of the material and carrying the more exposed portions below the moisture content desired. It also brings the average moisture content slightly below that required, although some portion of the material may have a greater moisture content than others. v

I have found that the-air after passing over and in contact with the material one or more times will assume a relative humidity corresponding to the moisture content of the material itself. It is well known that the moisture content of any hygroscopic material will correspond tc a definite relative humidity of the air in contact with such material. I have also found that if the relative humidity of the air after having come in contact with the material one or more times is regulated for some predetermined relative humidity, the moisture content of the material will be fixed at the desired percentage which will correspond to the predetermined relative humidity. lThis isthe principle of the control which I have employed in my process. Throughout the specification and claims, wherever the term conditioned is employed as applied to air, I mean such air as has been so treated as to have a predetermined temperature and moisture content.

It will be noted that the conditioned air and the material are introduced into the chamber at the same endand that the general course of travel of the forced currents of conditioned air is substantially coincident with the direction of travel of the material being treated. The fans provided in each chamber drive the air in the chamber between and in contact with the material in cross currents; and, as the material travels through the chamber, the air will be forced to come into contact with it one or more times. At the opposite end of the chamber the air and the materia-l will be discharged, and it is at this point (after the air has come in contact with the material for the last time) that the control instrument or instruthe materialsl being treated can be fixed at any desired predetermined percentage and that the automatic regulation is sosensitive Obviously some modifications may be made without departing from the spirit of my inventions or the scope of the appended claims; and, therefore, I do not wish to be understood as defining only the exact way in whiclrthe process may be carried out.

I claim- 1. A process for progressively treating hygroscopic materials. comprising the sub- `iection of the materials being treated to conditioned air during the preliminary stages of treatment, and then fixing the final desired condition of the materials by means of and in accordance with the condition of the air during the final stage of treatment.

2. A process for progressively treating h ygroscopic materials, comprising the subjection of the materials being treated to comparatively dry air during the first stage of treatment, and then fixing. the moisture content of such materials at any desired stage of the treatment by means of the predetermined temp'eratu're and relative humidity of the air, after it has come in contact with the materials during that stage of the treatment. i

3. ,A process for progressively treating hygroscopic materials, comprising the sub- `iec'tion of the materials being treated to comparatively dry air, the'temperature of which alone is controlled, and then subjecting the materials to conditioned air the temperature and the moisture content of which are both controlled.

4L A process for progressively treating hygroscopic materials, comprising the subjection of the materials being treated to previously saturated air having a substantially fixed dew point and a variably increased temperature which corresponds to the moisture content of the materials after the air has come in contact with the materials one or more times.

5. A process for progressively treating -hygroscopic materials, comprising the subjection of the materials being treated to com-i paratively dry air having a relatively high temperature which alone is controlled during the first stage oftreatment, and then subjecting the materials to conditioned air having a lower temperature andV higher moisture content during the succeeding stages of treatment.

6. A process for progressively treating hygroscopic materials, comprising the passage of the materials and conditioned air through a plurality of treating chambers in the same direction and causing the air to come into contact with the materials one or tid -ioo

atenuar more in each chamber, and then predetermining the desired relativehumidity oi the air which is in contact with the'materials in the last of such chambers, thereby fixing the desired moisturecontent'of-the materials after they have been treated. I 7. A process for progr ssivelyy treating' hygrosc'opic materials, com rising the subjection of the materials being treated to conditiored air of 'high temperature and hi b mo' ure content, and then .subjecting tile erials to air having a lower temperature fan moisture content but higher relative humidity. \8. A process for progressively treating hygrosc'o ic materialsfcomprising the subjection o the aterials being treated to conditioned air having a', fixed high tem eraturc and high moisture content whereby-t e mois- `ture content of the materials is' substantially lower. than iinallydesired, then/subjecting the materials to conditioned air having aA lpredetermined lower temperature and a ow moisture content but higher relative humidity, whereby the final moisture content of the materials Ais increased to the desired fixed .amount.

9..A processv for progressively treating -hygroscopic materials, comprising theg'sub-P jection of; the materials being treatedto con# ditioned 'air during the preliminary of I treatment, and then subjecting. the -materials torelatively'cool, moist air'durln'g subse quent stages of treatment.

10. A process for progressively treating hygroscopic. materials, comprising first the subjection ofthe materials beng treated to cx'mditi'oned air -duri'n' the preliminary stages of treatment, en subjecting the "materials torelatively cool, moist air, and

then, d the'nal treatment, fixing the condition o the materials' by means of the conditioned air.

' 11. Aprocess Yof progressively,*treating* hygroscopic materials, comprising vthe subjection of-the materials bein treated to conditioned air, and then su the v.materials to Vconditioned airjhavmg a lower 'temperature andA moisture content but'a higher. Yrelative 'humidity than the conditionedf'airiirst mentioned. f'

hygrosco 1c materials comprising the` sub` -jection o 'the being treated to con-l ditionedA air, and` then subjectingthe' mate- Vrialsto. previously saturated air having a relativelyglow fixed dew point.

@ 13. A for progressively treating hy'grosccl 1c .materials comprising thev Sub?. jection o the materials being treated to con-.

-rials to previously "empli-ated' air havin va.-

air` first mentioned.

hyg'roscopicv materials comprising the subjecton of the materials being treated to conditioned air during the preliminary stages oftreatment, vand then adding moisture to the materials during the final treatment by means of xinditionedI air.

' -15. A processfor progressively treating hygroscopic materials, comprising the .subjection of the materials being treated to conditioned air during the preliminary stages of treatment, the temperature and relativehumidity of which arecontrolled, then add-- ing moisture to the materals duri thenal .treatment by means of relat'v y cooler,

14. A yprocess for'progressively treating moist air, and fixing'the vfinal desired condition of the materials by means of the last mentioned air by automaticall controlling the relative humidity ofthe a1r during final stage of treatment.

16. A process for progressivelytreating i '.hygrosco'pic materials, comprising thev subjection of the materials being treatedto conditioned air during theA prelimnary stages of 'treatment,and then duringsubsequent stages 'f treatment subjecting the materials to previously saturated air, having '-a lixed de'wA point and controlling theA temf-periature-of the airso thatthe -final desired condition of; semanas-is and by the conditin'o'f theair.

117. Av process -for progressvely ..treating hygrosco ic materials, comprising -the subjection,o the materials being treated to, conditioned' air during the 'prelimina of treatment, and then stages of treatment subjecting stages t e materials su sequent to prevously saturated air and predetermining the relative 'humidity'of` the air` by controlling its temperature, so that' the final, de sired condition of the materials is fixed by the condition of the air.

18. A process for progressively treating hygroscopic materials, comprising the subjection of the materials to air currents in which the temperature alone is ontrolled, 'then" subjecting the materials to 4a currents in which the tem rature and relative 'humidity are contro led, 'andi then subjecting Vvthe material toair currents inwhichthe Y Y temperature alone is controlled; :1 2. iA. process Vfor progressively-treating 19. A process for progressively treating hygrosco ic materials,` comprising the' subjection o materials to air currents in which the temperature alone is controlled, -then 1 subjecting the materials to air' currents. havhumidity thanthe air currentsV nicn-l 20. A vprocese for progressvelytreating hygrosco icmater'ials, comprising the subjecton'o materials to air rvfhclzV ture content of such materials as they are the temperature alone is controlled during the preliminary stage of treatment, then during asubsequent stage of treatment subjecting the materials to air currents, having a lower` temperature and a lower moisture content but a higher relative humidity than the air currents first mentioned, and then during the final stage of treatment subject- ,ing the materials to air currents having a higher relative. humidity than the air currents last mentioned.

21. A process for progressively treating hygroscopic materials, comprising the subjection of the materials being treated to comparatively dry air, the temperature of which alone is controlled, then reducing the moisture content of such materials below that desired in the finished materials by means oi conditioned air, and then adding to the moisi finally treated bymeans of conditioned air.

22. A process for progressively treating hygroscopic materials, comprising the subjectionof the materials being treated to comparatively dryair currents, the temperature of which alone is controlled, then subjecting the materials to air currents having a lower temperatureand a higher relative humidity than the air currents first mentioned, and

aojthen subjecting such materials to air currents having a lower temperature and a higher relative humidity than the air currents-last mentioned.

23. A process of progressively treating hygrosco ic materials,'comprising the sub-v jection o the materials being treated to comparatively dry air currents during the preliminary stages of treatment, the ltemperature of which alone is controlled, then during the subsequent stage of treatment subjecting the materials to air currents having a lower ter'nperature and a higher relative humidity than the air currents first men.- tioned,then during `the next stage of treat.- ment supplying saturated' air having a fixed dew point, and the final temperature of this saturated airA after coming in contact withv the 'material for the last timel being regu- ,lated ata .predetermined temperature.

. 24. A process for progressively treating `hygroscopic materials, comprising the subjectionof the materials to air currents having a high temperature and a comparatively low moisture content, then subjecting the materials to air currents having a lower temperature and high moisture content, land then subjecting the materials to air currents having a lower' temperature and a lower moisture content but a higher relative humidity.' i A 25.' A process for progressively treating hygrosco ic materials, comprisingV the subjection o` the materials to air currents having a high temperature and a comparatively low moisturecontnt during the preliminary meanest 'ties of the air being automatically cont :.olled and predetermined as desired. ,y

26. A process for progressively treatingl hygroscopic materials, comprising the subjection of the materials to air currents having a high temperature and a comparatively low moisture content during the preliminary stage of treatment, then during a subsequent stage 'of treatment subjecting the materials.

to air currents having a lower temperature and high moisture content, and then during subsequent stages of treatment subjecting the materials to air currents having a lower temperature and a lower moisture content but ahigher relative humidity, the conditions of thematerials being fixed by means of the predetermined temperature, moisture contents, and relative huinidities of the air during each stage of the treatment.

27. A process for progressively treating hygroscopic materials, comprising the subjection of the materials to air currents ul.-

timately movingsubstantially in the same direction as the material, ,causing said air currents to come in contact with and between the materials one or more times, thereby obtaining an interchange of moisture between the air and the materials, controlling such interchange by varying the relative humidity of the air currents initially in contact with Vthe materials, such variation being governed b'y the final relative humidity of the air currents after last coming in contact with the materials.-

*$28. A process for progressively treating hygroscopic materials, comprising the subjection of the materials substantially to saturated air currents of a tixed dew point ultimately moving substantially' in the same direction as the material, causing said air currents to come in contact with and between the materials one or more times, thereby having the materialsabsorb moisture from said air and simultaneously controlling the regain in the materials by varying-the temperature to which the saturated air currents ofa fixed dew point are heated prior to their initial v 29. A process for progressively treatingl hygroscopic materials, comprising the subljection of the materials to ,air currents of a `fired dew point ultimately moving substantially in the same direction as the material,

materials, such variation bein? causing 'sa-id air currents-"tebome in contact with the materials-while maintaining sub' 25 with and between the materal'sgone ormore tmes,t thereby having thematerials absorb moistureafrom saidalr and simultaneously controlling-the regain in the materials byvarying the-volume of such saturated air of fixed dew-point coming in contact with the governed by the iinal relative humidity o the air currentsafter last coming in lcontact with the materials. v I

.30, A process for progressively treating hygroscopic materials, 'comprising the subjection of; the materials toV air currents of a constant wetbulbtemperature and a variable dry bulb'temperature ultimately moving substantiallyin' the same direction asthe material, causing said air currents to come in contact withend between the materials one or more'times, thereby obtaining an interchange of moisture between the air and A thematerials and simultaneously controlling lsuch, interchange by the dry bulb tempera .ture of the airfcurrents initially' in eontaet stantially a constant wet bulb temperature throughout the treatment, such variation beingigoverned by the nal dry bulb tempera-A ture of the air currents after last coming in contact with the. materials.

31. A p ocess :for progressively treating hygroscopi materials, comprising the subjectionof the materials to air currents ultimately moving substantially in the same dil reetion as the material, causing said air eur' rents to come in contact with and between the materials one or more times th reby obtain-A ing an interchange of moisture between the air and the materials, controlling siich inter change by regulating the final dry and Wet bulb temperaturesof the air currentsY after last coming in contact with the materialsin decreasmg or increasing the mplsture con tent of the air currents initially in contact with the materials.

4 In testimony whereof, "I have hereunto signed my name.

ALFRED CHARLES YBUENSOD.

Certcate ci? Cerreeton, lt is hereby certified -that Letters Patent No.v 1,567,031, granted December 29,

n 1925, upon the application of Alfred Charles Buensod, of New York, N. Y., for an improvement 1in Processes for Treating Hygroscopic Materialsf? an 'error appears follows: 1n the drawings, Sheet 1, containing Figures 1 and requirimlr correction as 2, should appear as shown below instead of as shown -1n thel drawings:

nd-thas the Said Letters Patent Should-be read with this correction therein mmh@ s e meay conform to the record of the case in-the Patent Oce. Sign land Sealed this 4th day of January, A. D. 1926. i [sun] v M. J. MOORE,` amnsazomr of P l 

